What Is an Omental Flap and How Is It Used in Surgery?

An omental flap is a piece of the greater omentum, the large, fatty apron of tissue that hangs from your stomach and drapes over the intestines, that surgeons detach (partially or completely) and move to another part of the body to help heal wounds, fill dead space, or fight infection. The omentum has been called the “policeman of the abdomen” for centuries because of its tendency to migrate toward sites of injury and inflammation on its own. What makes it exceptional as surgical raw material is its dense blood supply, its ability to stimulate new blood vessel growth, and its pliability, which lets it be shaped to fit defects ranging from a sternal wound to a scalp injury to the inside of a pelvis.

Why the Omentum Is Uniquely Suited for Repair

The omentum is not just a sheet of fat. Scattered throughout it are clusters of immune-active tissue called milky spots, and the whole structure is laced with blood vessels fed primarily by the gastroepiploic arteries and veins running along its upper edge. When the omentum is stimulated by injury or a foreign body, the non-fat portion of the tissue (those milky spots) can expand by fifteen- to twenty-fold, blood vessel density triples, and concentrations of growth factors like VEGF rise two- to four-fold.¹ This transformation turns the omentum into a tissue-repair factory.

The key molecule behind much of this activity is vascular endothelial growth factor, or VEGF, which drives the formation of new blood vessels. Research has shown that the omentum produces more VEGF than other tissues, and that the fat cells within it are the primary source of that protein. Under low-oxygen conditions, omental fat cells ramp up VEGF production by roughly 1.7-fold, which helps explain why the omentum is so effective at rescuing tissue that has a poor blood supply.² In practical terms, if you need to bring blood flow and healing capacity to a wound that would otherwise struggle to close, the omentum is one of the best tissues in the body for the job.

How Surgeons Harvest and Position the Flap

Surgeons use the omentum in two basic configurations. In a pedicled flap, the tissue stays connected to its original blood supply through the gastroepiploic vessels. The omentum is separated from the colon and stomach, lengthened if needed, and then tunneled through the abdomen and chest wall (or wherever the target wound is) while still attached at one end. This is the simpler approach and avoids the need for microsurgery. The second option is a free flap, where the omentum is completely detached and transplanted to a distant site. The surgeon then reconnects the gastroepiploic vessels to arteries and veins near the wound using microsurgical anastomosis.³

Traditionally, harvesting the omentum meant a large abdominal incision. Increasingly, surgeons perform the harvest laparoscopically, using small incisions and a camera to dissect the omentum free before extracting it through a mini-incision. In one series of twelve patients treated with laparoscopically harvested free omental flaps for complex wounds, all flaps survived (with only one case of minor partial necrosis at the flap edge), and every donor site healed without major complications.⁴ The shift toward laparoscopic harvesting has reduced postoperative pain at the donor site and shortened hospital stays.

The omentum’s vascular anatomy is fairly consistent but does have variations. Imaging studies have identified six different course variations of the gastroepiploic vessels, and the artery and vein tend to be larger in men than in women. Along the vasculature, there are typically about three clusters of lymph nodes, which become important in lymphedema surgery.⁵

Sternal Wounds and Chest Infections

One of the most established uses of the omental flap is rescuing deep sternal wound infections after open-heart surgery. These infections, sometimes called mediastinitis, are dreaded complications that can be life-threatening. The sternum has been sawed open, and if the wound becomes deeply infected, the bone and surrounding tissue may not heal with antibiotics and debridement alone. The standard surgical rescue has long involved rotating a chest muscle (like the pectoralis major) into the wound. But the omentum offers an alternative that some surgeons prefer, especially when infected hardware such as sternal wires or prosthetic material is involved.

In one series, omental flap reconstruction achieved complete wound healing in every patient, with no flap loss and no recurrence of the deep infection, even when potentially contaminated artificial material remained in place.⁶ The same procedure has been performed laparoscopically, with surgeons reporting smooth recovery and good wound healing with minimal discomfort at the harvest site.⁷

The omentum has also been used in lung transplantation. Some surgeons wrap it around the bronchial anastomosis (the connection between the transplanted lung’s airway and the recipient’s airway) hoping to improve healing and prevent breakdown. Animal studies showed promising results, with omental wrapping significantly reducing narrowing at the anastomosis compared to controls.⁸ However, a randomized trial in human lung transplant patients found that wrapping the anastomosis with omentum did not reduce the rate of bronchial complications.⁹ This is a useful reminder that promising animal results do not always translate to clinical benefit, and practices around omental wrapping in lung transplantation remain varied.

Pelvic Reconstruction After Cancer Surgery

When surgeons remove pelvic organs for cancer, whether through a total pelvic exenteration or abdominoperineal resection, they are left with a large, empty cavity that is prone to infection and slow healing. Filling that dead space with living, well-vascularized tissue is critical. The omental pedicle flap is one of the two most commonly used flaps for this purpose, alongside the vertical rectus abdominis myocutaneous (VRAM) flap.¹⁰

A retrospective study comparing patients who received omental flaps after pelvic exenteration to those who did not found a significant reduction in pelvic infection in the flap group.¹¹ The omentum’s immune properties and rich blood supply help resist bacterial colonization of the dead space. In some cases, the omental flap has been combined with synthetic dermal matrices to reconstruct the pelvic floor itself.¹²

Head, Neck, and Scalp Coverage

The omentum might seem like an odd choice for reconstructing the head and neck, given the distance from the abdomen. But for large, contaminated, or previously irradiated wounds where local tissue is insufficient, a free omental flap can be a lifesaver. The tissue’s pliability lets it conform to the irregular contours of the skull, face, and neck, and once in place, it accepts skin grafts well.

In one report of a total traumatic scalp avulsion in a 50-year-old man, surgeons successfully covered the entire exposed skull using a free omental flap harvested laparoscopically and covered with a skin graft. The flap survived completely and provided full coverage of the calvarium.¹³ For pharyngeal (throat) reconstruction after cancer surgery in irradiated tissue, surgeons have used gastro-omental flaps, where the omentum is transferred along with a tube of stomach wall to rebuild the swallowing passage. Patients resumed eating by mouth within a week.¹⁴

The advantage in irradiated wounds is worth emphasizing. Radiation damages local blood vessels, leaving tissue poorly supplied and slow to heal. The omentum brings its own blood supply and its VEGF-driven ability to stimulate new vessel growth into exactly the kind of starved tissue that needs it most. A series of thirteen patients with complicated, contaminated, or irradiated head and neck wounds were successfully reconstructed with free omental transfers in a single surgical stage.¹⁵

Lymphedema Treatment

A newer and rapidly evolving application for omental tissue is treating lymphedema, the chronic swelling that can develop when lymph nodes are removed or damaged during cancer treatment. Those lymph node clusters along the gastroepiploic vessels can be transplanted along with the omental tissue to a limb where lymph drainage has been disrupted. The idea is that the transplanted lymph nodes establish new drainage pathways.

In a series of 42 patients who received free omental lymphatic flaps, about 83% reported subjective improvement, and average limb volume decreased by roughly 22%.¹⁶ Individual cases have shown even more dramatic results. One patient with lymph node depletion in the upper limb had arm circumference reductions of about 43% above the elbow and 36% below the elbow within eight months of receiving an omental lymph node flap.¹⁷

Perhaps most intriguing, there is evidence that transplanted omental lymph nodes can actually reconnect to the recipient’s existing lymphatic network. Imaging in one patient nine months after omental lymph node transfer showed radiographic evidence of spontaneous lymphatic reconnection.¹⁸ If this finding holds up in larger studies, it would suggest that the omentum does not just provide passive drainage but actively integrates with the body’s lymphatic system at the new site.

Brain Revascularization and Bone Infections

Among the more unexpected uses, omental flaps have been employed for indirect cerebral revascularization in Moyamoya disease, a condition where arteries at the base of the brain progressively narrow, starving brain tissue of blood. The omentum, with its angiogenic properties, is laid onto the surface of the brain. Over time, new blood vessels grow from the omentum into the brain tissue, creating a supplementary blood supply. A ten-year retrospective study found that laparoscopic pedicled omental flap transposition was a safe and effective method of achieving this indirect revascularization.¹⁹

In orthopedic surgery, the omentum has been used to treat chronic bone infections (osteomyelitis) of the lower limbs that resist conventional treatment. These cases often involve bone that has been debrided extensively, leaving a large soft-tissue defect with exposed, infected bone. The omental free flap provides both dead-space obliteration and soft-tissue coverage, and its infection-fighting properties can help eradicate chronic illness that has persisted for years.²⁰ A separate report confirmed the flap’s usefulness specifically for infected wounds when combined with bone reconstruction techniques.²¹

How Omental Flaps Compare to Muscle Flaps

The omentum is not the only tissue surgeons can mobilize for wound coverage. Muscle flaps, particularly from the pectoralis, latissimus dorsi, and rectus abdominis, are the traditional alternatives. The choice between the two depends on the wound’s location, size, and whether infection is a concern.

In the chest, a comparison of omental pedicle flaps and muscle flaps for closing open-window thoracostomies (a procedure used for chronic chest cavity infections) found significant differences. Local infection recurrence was 0% with omental flaps versus 50% with muscle flaps, and the median hospital stay was about 16 days with omentum compared to about 42 days with muscle.²² That is a stark difference, though the study was small and the results need confirmation in larger groups.

At the tissue level, there are differences in how the two types of flaps heal. In an experimental comparison of omental versus muscle flaps over stomach wall defects, both achieved surface coverage by day seven, but the scar tissue in the muscle group persisted, while in the omentum group it was gradually replaced by adipose tissue.²³ The omentum’s tendency to remodel toward softer, more natural tissue rather than rigid scar may be an advantage in certain reconstructive settings where pliability matters.

That said, muscle flaps have their own strengths. They provide structural bulk that the omentum cannot, they are available at donor sites closer to the wound in many cases (avoiding the need for an abdominal operation), and they carry their own skin, eliminating the need for a separate skin graft in some procedures. The omentum shines when the wound is infected, irradiated, or unusually large, or when the goal is angiogenesis rather than structural reinforcement.

Risks and Complications

Harvesting the omentum is generally well tolerated, but it is not without risks. A review pooling complication data from omental flap procedures in thoracic surgery found that about 15% of patients experienced postoperative bleeding (half of whom were on blood-thinning medications), and roughly 20% developed an incisional hernia at the harvest site. Overall perioperative mortality in that series was about 2.5%.²⁴ Hernia is the most talked-about donor-site concern, and it appears to be more common when the omentum is routed through the anterior chest wall rather than through the diaphragm.

Other possible complications include injury to adjacent abdominal structures during harvest, postoperative ileus (temporary shutdown of bowel activity), and flap-specific problems like partial necrosis or dehiscence. Laparoscopic techniques appear to reduce some of these issues, particularly abdominal wall complications. In one series of laparoscopically harvested flaps used for chest wall reconstruction, none of the patients had major intra-abdominal complications, though one developed a small hernia through the diaphragm that was repaired laparoscopically.²⁵

Previous abdominal surgery can make omental harvest more challenging because of adhesions (scar tissue binding the omentum to other structures), but it does not necessarily rule it out. Surgeons have successfully used omental flaps even in patients with significant prior abdominal operations.²⁶

Breast Reconstruction

Breast reconstruction is one area where omental flaps are gaining attention as an alternative to more traditional approaches like implants or tissue flaps from the abdomen or back. In a pedicled approach, the omentum is tunneled up to the breast through the upper abdomen. As a free flap, it is transplanted to the chest and connected to the internal mammary vessels using microsurgery. A systematic review of breast reconstruction with omental flaps found that about 89% of patients reported satisfactory cosmetic results, and professional assessment rated the outcomes favorably in about 80% of cases.³

The omentum’s softness produces a natural feel, and the tissue can be combined with fat grafting to achieve additional volume over time. The main limitation is size: the omentum may not provide enough volume for larger breast reconstructions, especially in thinner patients whose omentum is correspondingly small. For partial breast reconstruction after lumpectomy, however, the omentum is increasingly seen as a good match.

Use in Children

The omentum is not restricted to adult surgery. Pediatric surgeons have used omental flaps in children for tracheobronchial reconstruction, an application where the stakes are high because airway anastomosis failure in an infant can be fatal. In a series of six patients aged four months to three years who underwent tracheal or bronchial reconstruction, an omental pedicle flap was used to reinforce the repair. None of the patients died from anastomotic leak, and four of the six were completely free of airway problems afterward.²⁷

Omental flaps have also been used in pediatric abdominal wall reconstruction. In complex abdominal wall defects, the omentum can be combined with synthetic mesh in a “sandwich” configuration, with the omentum providing the vascular bed that helps the mesh integrate and resist infection. A case report described successful use of this technique in a child, noting that the combination was more effective and safer than mesh alone.²⁸ Pediatric patients also present unique challenges in omental harvest because the tissue is smaller and the vascular pedicle is proportionally shorter, but the omentum’s regenerative capacity appears to hold regardless of age.

Complex Upper Extremity Wounds

Severe hand and arm injuries with large tissue defects, exposed tendons, or bone represent another niche where the omental free flap has been used with success. A retrospective analysis of eight omental free-tissue transfers for complex upper-extremity defects, with patients ranging from age 12 to 59, found that all achieved complete wound coverage with no flap loss or major complications. The average defect covered was nearly 300 square centimeters.²⁹ The authors referred to the omentum as the “forgotten flap,” reflecting a common observation among reconstructive surgeons that the omentum is underused relative to its versatility. Its thin, drape-like quality makes it especially suited for wrapping around irregular structures like tendons and joints, and the overlying skin graft tends to produce a cosmetically acceptable and functional result.